This invention relates to the box forming art. More particularly, this invention relates to a method and apparatus for forming a tray from a paperboard flat blank, wherein the formed tray includes a pair of horizontally disposed shoulders at opposite ends of the tray. When the formed tray is used, the horizontally disposed shoulders facilitate stacking and also function to retain articles within the tray which are located adjacent to the end walls thereof.
The automatic formation of such a tray from a flat blank is a particularly difficult task because, when the tray is formed, the horizontally disposed shoulder panels close off a portion of the top opening of the tray. As a result, the area of the opening at the top of the tray is smaller than the area of the bottom of the tray. Generally, paperboard trays are formed on automatic tray forming machines wherein a mandrel is employed in such a manner that the box blank is wrapped around the mandrel during for forming sequence. After the tray is formed, the mandrel is vertically withdrawn from the tray. However, with trays of the type hereinbefore described, i.e., trays with horizontally disposed shoulder panels, a conventional mandrel cannot be employed because, after the tray is formed, the horizontally disposed shoulder panels would inhibit vertical withdrawal of the mandrel. Additionally, conventional tray forming machines do not include appropriate folding means for correctly positioning the shoulder panels and the maintaining panels connected thereto.
The machine hereinafter disclosed accepts appropriately cut and scored flat blanks and automatically folds each blank to form a tray having horizontally disposed shoulder panels.